The present invention generally relates to seat belt retraction mechanisms and more specifically to an improved vehicle deceleration responsive sensor. Such type of sensor is often called, in the art, vehicle or inertia sensors.
Seat belts and retractors are commonly used as part of a safety restraint system to protect vehicle occupants. A typical retractor includes a spool, a frame for supporting the spool, a locking mechanism(s) to stop the spool from rotating and web and/or vehicle sensors for initiating spool lockup upon sensing certain dynamic criteria.
A practical seat belt retractor should of course be of low cost and of high quality. The underlying design must be flexible to accommodate varying customer performance criteria. Such criteria will generally include, in addition to the above: small package size to permit the retractor to be easily fit into virtually any location and any orientation within a vehicle, and light weight construction. In addition, the retractor should be relatively easy to manufacture and have a design amenable to automated manufacturing techniques. The retractor should be characterized by low belt extraction and retraction forces and an overall quiet operation. The retractor should be capable of using one or more sensors such as a web sensor and vehicle sensor without a major change in the basic structure of the retractor and be smooth in its operation and not jam, as well as be capable of withstanding loading forces in the range of 18 KN. With regard to the vehicle sensor, such sensor should be flexible in its design to accommodate working with a retractor that is mounted in a tilted or skewed positioned.
It is the object of the present invention to provide an improved seat belt retractor having an improved vehicle sensor.
Accordingly, the invention comprises: a retractor including a vehicle inertia or deceleration sensing device for and including a seat belt retractor comprising: an outer housing member including a first or outer housing part for supporting an inner housing member at a predetermined relative angle. The first housing part includes first and second coordinate reference axes superimposed therein. The inner housing member comprises: a second or inner housing part which includes an outer surface, a portion of which has a diameter of r 1 measured from a geometric center of the second housing part and an inner surface. The second or inner housing member or part also includes at least one extending leg member having an end which defines a hinge axis. An activation portion is pivotally connected at the hinge axis and includes a spherically shaped, top surface having by a radius of r 1 and an under surface. Located in the inner member is an inertial member, responsive to changes in vehicle acceleration or deceleration and movable relative to the inner surface of the second housing part. The inertial member also supports the under surface of the activation portion, such that in a rest position, the spherical top surface of the activation portion is positioned on a sphere of radius r 1, centered at the center of the second housing part. The invention further includes first means for fixedly mounting the second housing part at a predetermined first angle about the first reference axis in the first housing part, such angular positioning not changing the height of the activation surface. A support member is provided for supporting the first housing part. The invention also includes second means for fixedly mounting the first housing part at a predetermined second angle, about the second reference axis relative to the support member, without changing the height of the activation portion, wherein in response to an acceleration or deceleration greater than a given magnitude the inertial mass moves relative to the inner surface, and moves the activation portion outwardly. Upon mounting the parts as described the inertialmember is maintained vertical.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.